Curtain for a watercraft



FIG. 1 is a perspective view of a curtain for a watercraft showing my new design, with the curtain in partially folded condition;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof; and

FIG. 4 is a side elevation view of FIG. 1. 

The ornamental design for a curtain for a watercraft, as shown and described. 